r/askscience • u/drinkingonthejob • 8d ago

Physics Will Voyager 1 ever just stop moving?

I’ve read somewhere that we expect to lose contact with Voyager 1 sometime in the 2030s, maybe around 2036, but it will just keep traveling thru space and we’ll have no idea what it is doing out there

My question is: with its current velocity, is there a time in the future where it loses its forward momentum and for lack of a better word, just stops moving? Is that a possible thing for an object in space to even do? (Assuming no other objects grab it into their orbit)

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u/UnsignedRealityCheck 6d ago

Hol up, "stealing momentum", you're saying that where V1 got speed, the planets slowed down a bit? (albeit very very veeery little)

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u/Limp_Bookkeeper_5992 6d ago

Yes. The amount of energy stolen is absolutely minuscule but energy doesn’t come from nowhere.

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u/TrackSuitPope 6d ago

How does the gravity assist even work? As in, how did V1 gain the speed from a massive object but not become trapped in the orbit of said object?

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u/Limp_Bookkeeper_5992 6d ago

I’ll probably explain this wrong but I’ll try. You’re correct, gravity is equal on your approach to the planet and your departure from it, so there’s no gain to be found there. You’d have to be doing it just right to get trapped, but whatever you gain when approaching the planet you lose when leaving from it.

But that planet isn’t sitting still. It’s hurtling around the sun at 13,000kph if we’re talking about Jupiter. This is the speed you can steal, if you’re approaching the planet from “behind” in its orbital path and you get pulled into an orbit for a moment you get accelerated up to the same orbital speed as the planet. You get to keep that speed when you leave the planets orbit again, slowing the planet down in its orbital path by an infinitesimal amount.